Hair transplantation procedures are well-known, and typically involve harvesting donor hair grafts from the donor areas, for example, side and back fringe areas of the patient's scalp or other surface containing hair, and implanting them in a bald area (recipient area). Historically, the harvested grafts were relatively large (3-5 mm), although more recently, the donor grafts may be single follicular units. In particular, “follicular units” (also referred to as FU or FUs) are naturally occurring aggregates of 1-3 (and much less commonly, 4-5) closely spaced hair follicles that are distributed randomly over the body surface, such as a scalp.
The follicular units may be classified, or “typed,” based on the number of hairs in the unit and identified in shorthand as an “F1” for a single hair follicular unit, an “F2” for a two hair follicular unit and so on for follicular units with 3-5 hairs. It is desirable to identify follicular units based on the number of hairs in the follicular unit. For one, it is preferable to transplant certain classes of follicular units into specific regions of the scalp. For example, single hair follicular units (F1s) are commonly implanted along the hairline that frames the face. Follicular units with more than one hair (F2s, F3s, etc.) are commonly implanted in the mid-scalp and crown. This arrangement of follicular unit distribution is thought to produce a more natural appearing aesthetic result. Still, it may be desirable to utilize a variety of classes (also referred to as “types”) of follicular units to provide the desired attributes for the appearance of the transplanted hair. Such attributes can include the density of hair, the direction or orientation of hair, the particular mix of types of follicular units, and/or the appearance of randomness, among other possible attributes.
Various procedures for hair transplantation have been previously disclosed, including both manual and mechanized to certain degrees of automation. In one well-known manual process, a linear portion of the scalp is removed from a donor area by dissection with a scalpel down into the fatty subcutaneous tissue. The strip is dissected (under a microscope) into the component follicular units, which are then implanted into a recipient area in respective puncture holes made by a needle. Forceps are typically used to grasp and place the follicular unit grafts into the needle puncture locations, although other instruments and methods are known for doing so. In another manual process, a hand-held punch or cannula is used to extract follicular units from a body surface one at a time for subsequent implantation in another location. This technique is known as FUE (follicular unit extraction) technique.
In utilizing any of the manual or automated systems and methods for hair transplantation, it is desirable to improve the speed and efficiency of the procedure. Regardless of the system used, certain time is often lost due to the need to select the next follicular unit to be harvested and to move the hair harvesting tool from the position of previously harvested follicular unit to the location of the next selected follicular unit. Therefore, there is a need for a system and method for automated selection mechanism for choosing follicular units for harvesting and improving efficiency of the process as a whole.